The Denver and Rio Grande Western K-27 is a class of 3 ft (914 mm) narrow gauge 2-8-2 "Mikado" type steam locomotives built for the Denver and Rio Grande Railroad by the Baldwin Locomotive Works in 1903.

Known by their nickname "Mudhens," they were the first and the most numerous of the four K classes of Rio Grande narrow gauge engines to be built.

In the D&RGW's classification system, K was short for MiKado while 27 referred to the engine's 27,000 lbf of tractive effort.

The extra maintenance costs of the two cylinders were greater than the fuel saving, so they were converted to simple expansion in 1907–1909.

Because the counterweights were outside the frames, they ended up directly over the standard gauge rail, with a clearance of only about 5⁄8 inch (16 mm).

[2] They pulled freight, passenger and mixed trains on the D&RGW in and over the Colorado Rocky Mountains, traversing the entire length of the railroad.

The Huckleberry Railroad in Genesee Township, Michigan, near Flint, acquired the locomotive in 1981, did an eight-year restoration on it, and put it into active service.

They ended up in three distinct groups, with many different details such as the location of the air tanks, whether or not they had a doghouse on the tender for the head brakeman, and so forth.